The Flow Cytometry Core Facility of the National Human Genome Research Institute has the goal of providing all NHGRI investigators with access to high quality flow cytometry services. The Core serves to enhance the scope and quality of scientific research performed by the Institute. In FY2012, the NHGRI Flow Cytometry Core was staffed by Stacie Anderson (Core Director, 100% effort, GMBB), and Martha Kirby (100% GMBB). The Core post-bac IRTA position is currently vacant and will remain unfilled for the foreseeable future. The Flow Cytometry Core is staffed Monday through Friday and is available to authorized users after regular working hours and on weekends/holidays through key-card access. The NHGRI Flow Cytometry Core currently maintains two BD FACSArias that are primarily used for sorting cells. Each FACSAria is configured with three lasers and can measure up to nine fluorescent parameters as well as physical parameters (size and granularity). The purchase of a fourth 561nm laser was approved in FY2011 and the laser will be installed on the newer of the two Arias. It is anticipated that this installation will occur before the end of the fiscal year. This laser will allow us to detect the red fluorescent proteins with more efficiency and minimize compensation in the red channels. Among the various applications over the past year, the sorting capabilities have been used for isolation of tissue cell populations for animal transplantation experiments; isolation of blood cell sub-populations for analysis of functional cellular properties and gene transcription profiles, as well as high throughput screening of enhancer regions. The FACSArias are operated by the Core Staff, typically have a two-week sign up waiting time and are currently used at near capacity. For direct flow cytometry analysis applications not involving cell sorting, the Flow Core offers two BD FACSCaliburs and one BD LSRII. The FACSCalibur instruments can measure up to four fluorescent parameters, and are routinely used for data acquisition and pre-sort analysis. Due to budget restraints, FACSCalibur E0807 has been removed from service contract saving the Core $10,000 in FY11 and will be traded in to BD and the assets ($10,000) will be used towards the purchase of the 561nm laser. Typical uses of the FACSCaliburs include analysis of GFP expression and cell cycle, as well as mutagenesis screening. The BD LSRII uses digital electronics and Diva software similar to the Aria and is used to perform 9-color analyses. This allows investigators to characterize cells in more detail before sorting on the Aria. The instrument is equipped with a High Throughput Sample (HTS) device gives the investigator the ability to analyze many samples in 96-well plate format without the need of sitting at the instrument during the acquisition procedure. The Flow Core maintains a CompuCyte iCys laser scanning cytometer (LCS). The LSC uses laser-based opto-electronics and automated analysis capabilities to simultaneously and rapidly measure biochemical constituents and evaluate cell morphologies. Current applications (100%) are focused on zebra fish projects including drug screens and blood development. The Flow Core also maintains a Miltenyi Auto MACS that is used for magnetic cell separations. The AutoMACS is often used as a pre-enrichment step prior to sorting on a flow cytometer. The FACSCaliburs, BD LSRII, iCys and Auto Macs are available during regular Core hours as well as after hours and on weekends. Over the past year, the services and capabilities of the NHGRI Flow Core have been taken advantage of by 60 trainees from 5 Branches/14 Sections in the Institute. In addition, the Flow Core continued to maintain CLIA accreditation in support of immunophenotype and protein expression studies used in NHGRI clinical research protocols. Core Statistics (FY12): NHGRI Branches served: 5 NHGRI Investigators served: 60 Recorded Core Visits: 963 Number of sorts: 238